Creating a CNAME record for each of the domain names or subdomains that you have within a hosting account will allow you to forward it to a different domain/subdomain. The forwarded Internet domain will lose all its records - A, MX etc, and will take the records of the domain it's being forwarded to. In this light, you cannot set up a CNAME record to redirect your domain name to a third-party provider and retain a functional e-mail service with the first provider. It's also essential to know that a CNAME record is always a string of words and not a number because it is commonly mistaken for the A record of the domain name being redirected. One of the major uses of a CNAME record is to forward a domain which you own through one provider to the servers of another provider when you have created a site with the latter. In this way, the website will appear under your own domain name, not under some subdomain provided by the third-party provider.